206 GTi 180 Main engine management fuse (#15) blowing

Anzactuck

Anzactuck

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Fellow Frogger
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I was driving around a few nights ago, and accelerated hard in 1st (foot to the floor from about 30km/h to 60km/h). A few seconds after this I noticed the engine had died, and wouldn't re-start. I found that the main engine management fuse in the engine bay fuse box had blown.
I walked to a nearby service station and bought some fuses, but the fuse blows as soon as the key is turned to ON. Which meant I had to walk 2km home and go rent a trailer with my spare ute, ughh!


This fuse, (number 15) is a 30 amp fuse, with the description:
"Throttle housing heater – Diesel injection pump – Oxygen sensor – Engine control unit – Air flow sensor – Ignition coil – Engine management solenoid valve – Diesel heater – Injectors - Variable engine timing solenoid valve - Variable engine air intake solenoid valve"

So far I have disconnected the 02 sensors, VVT solenoid, Injectors, Coil rail, Throttle body, Fuel pump (all still blew the fuse)
I disconnected the ECU and it didnt blow, but I'm not sure if that means anything as the ECU just tells most of these other components to do their thing I'd assume, so its just like a link in the chain.
The ECU still communicates with my scan tool, and I have a bunch of codes (obviously):

P1292 - Dual inlet. Activation of second air intake duct. Circuit, lower malfunction
P0261 - Injector 1 circuit low
P0264 - Injector 2 circuit low
P0267 - Injector 3 circuit low
P0270 - Injector 4 circuit low
P0076 - Intake valve control solenoid circuit low
P0351 - Ignition coil A primary/secondary circuit
P0352 - Ignition coil B primary/secondary circuit
P0353 - Ignition coil C primary/secondary circuit
P0354 - Ignition coil D primary/secondary circuit
P0135 - 02 sensor heater circuit sensor 1
P0141 - 02 sensor heater circuit sensor 2
P0012 - Camshaft position timing over retarded

But this makes perfect sense for that fuse simply being broken, except possibly for P0012... but I suspect it's related to the fuse.
This fuse is responsible for SO MANY THINGS! Does anybody know where the relays are located? Are they integrated into the fuse box, as a sealed unit? I can't seem to find the information I'm looking for in that regard.
I want to now check relays but that is where I'm stumped, as I have no idea where they are yet. And if it is simply a shorting wire somewhere, how the hell do I find that when it could be one of 10 different circuits?

Anyway I'm just putting this out there in the hopes there is something common that I'm missing, or to at least enrich the internet with my Pug woes.
 
Can't help you with the relay location but can help with diagnosing it. At the fuse terminal, with the ignition on, you would have 12V at one pin and earth at the other due to your short. You need to disconnect related components until there is no longer earth continuity at that pin and that should direct you to the component causing the short. Remember to switch off the ignition each time you disconnect a component so as not to risk damaging it.
 
Bluey said:
Can't help you with the relay location but can help with diagnosing it. At the fuse terminal, with the ignition on, you would have 12V at one pin and earth at the other due to your short. You need to disconnect related components until there is no longer earth continuity at that pin and that should direct you to the component causing the short. Remember to switch off the ignition each time you disconnect a component so as not to risk damaging it.
Click to expand...
Ive gone through the rest of the components now (using a diagnostic fuse that auto-resets after shorting) and no matter what is disconnecred, it still trips the fuse.
The other thing I noticed is BOTH sides of the blown fuse are grounded.
Thats not right is it...
As in with a test light connected to the + terminal, both sides of the blown fuse will complete a circuit, connecting to ground.
This is with the key at Accessory and/or ON.
But it only blows when it moves to ON.

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Anzactuck said:
I disconnected the ECU and it didnt blow, but I'm not sure if that means anything as the ECU just tells most of these other components to do their thing I'd assume, so its just like a link in the chain.
The ECU still communicates with my scan tool, and I have a bunch of codes (obviously)
Click to expand...
The ECU can have multiple power feeds which is why you can still connect to it, there is likely a relay which is engaged to power on the #15 fuse and everything connected to it, which is its self enabled by either the ecu or direct from the ignition switch. Can you try disconnecting this #15 feed from the ECU connector and keeping the other wires in place?

Anzactuck said:
Ive gone through the rest of the components now (using a diagnostic fuse that auto-resets after shorting) and no matter what is disconnecred, it still trips the fuse.
The other thing I noticed is BOTH sides of the blown fuse are grounded.
Thats not right is it...
As in with a test light connected to the + terminal, both sides of the blown fuse will complete a circuit, connecting to ground.
This is with the key at Accessory and/or ON.
But it only blows when it moves to ON.
Click to expand...
The self resetting fuse is convenient but it still won't show you where the problem is. An old technique is to use a lamp in place of the fuse, something rated for much less than the fuse so say 10W or 15W. This gives you several ways forward:
If everything is disconnected form the line the lamp will only light from a wiring short. Most shorts are from wearing through the insulation jacket and when you start shaking looms the lamp will flicker when you get near the problem.

If there are some odd things happening with the feed to the fuse then you will be able to observe them at a leisurely pace, since the lamp won't blow like your fuses.
 
@hypermiler
The lamp method sounds great, I may have to try that (or a similar method with a test light, etc) soon.
Ive been reading a few threads about people having similar problems to me, some with the same engine, and some with the 1.4diesel which apparently uses the exact same engine fuse box/relay unit. Some people have managed to solder on external relays even.
I just dont feel as confident with this kind of electronic fault finding as I would if it were just one defined component and its wiring.
I dont have a wiring diagram (yet) and so Im not sure which wires to pull on the ECU or what effect they would have really.
In any event I paid $97 to get a 2nd hand engine fuse box to see what happens, as they are notorious (apparently) for having issues with the relays. Or... I wouldnt say they are notorious except for the fact that if any one relay has an issue then the whole unit is toast! Every car has a little relay issue here and there. I once fixed a friends air conditioning by just tapping his relay (obviously we then replaced it).
But these units have multiple function/component relays and aghhh. I miss my old diesel hilux, computer free!

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So as an update I fitted the spare fuse board and it reacted in the same way, telling me the relay was probably fine. Oh well now I have a spare!
So I spent some time making about 16 bridging wires to use on the connections from the relay/fuse board to the components.
The idea was Id disconnect individual bridging wires untill the short stopped, and then follow that one particular wire to wherever it led.
Im good enough with electronics to at least do that once I natrowed it down to a single circuit.
Anyway it was easier than that, as one of the wires immediately exploded (dramatized way of saying it heated up and destroyed itself within 1 second). Which I knew was a possibility as the wire was thin like speaker wire.
A few double checks and Im now mostly positive that is the short circuit.

Too sleepy to delve any deeper tonight but tomorrow eve I will undo some panels and follow it around!
Anybody know what this blue wire might be for?
In the plug you see me working on here, it is the bottom left connection while standing over the engine bay (towards front right of the car). Blue wire seems to go down into the front of the wheel/fog lamp/Secondary air pump area under the ABS valve body. Have to remove the inner guard to have a proper look

1532696264382.jpg1532696337547.jpg1532696343942.jpg1532696347132.jpg

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Forgo the colour - see if you can make out the 4 digit number printed on the wire.

The wire numbers are what Peugeot use to identify individual circuits, not necessarily the colour.
 
SLC206 said:
Forgo the colour - see if you can make out the 4 digit number printed on the wire.

The wire numbers are what Peugeot use to identify individual circuits, not necessarily the colour.
Click to expand...
I think it was as 1320P which I think is related to the ECU from a google search.

With that wire disconnected only (and thus the short not shorting) my scan tool was reading only Injector Circuit Low on all injectors.

That was kind of confusing too so I went and talked to this mechanic (Charles St Auto in Unley SA) and he told me he once had a GTi180 with a similar problem, related to the injector curcuit. He said it took him a week or two and he had the whole engine loom opened up and it turned out to be this random plug under the intake manifold.
Im not even sure what its for, it seems to take air and put it in contact with the manifold like a manifold heater or something. Theres a hollow chamber under the manifold connected with air lines.

Anyway long story short I unplugged it like he mentioned and the car started no problem.
Like he said Peugeots have some sttange wiring set ups!

Im pretty sure it was shorting onto the starter motor. But Ill clean it all up and put the car back together momentarily and make sure

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And so to finalise things I suppose, this is the component that is the short. Its not the wiring leading up to it (which was resting on the starter moter) but the actual component valve itself:

1533880237246.jpg1533880243278.jpg1533880246153.jpg

So I will try to get one of these valves, but its no issue running with it. It doesnt cause any codes to come up.

It's a funny little system, I suppose it's called an "oil vapour system"
There is one hose that takes crank case ventilation to a box under the manifold. This box then has the pictured hose come from it, back to the air intake pipe (before the throttle body). So it's like a typical single crank case ventilation pipe altogether, but maybe is cleaner?
The little electronic valve you see pictured has the small pipe shut off. This small pipe when open takes some of the oil vapour and plugs in just after the throttle body.
So... Im not exactly sure why this is, and can only assume it's a complicated emissions system.

The canister under the manifold is literally just an aluminium chamber, solidly mounted against the intake manifold (heat transfer?), but it has an oil gallery run through it too, so I think that acts as an oil cooler as it runs through the chamber, which would also heat the oil vapour... I dont even know!

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Here is a diagram I found on a Polish website talking about a 307.
You can see the oil ventilation pipes, going to the little chamber with the oil return pipe running through it.

1533881185516.jpg

Note: the top of the canister is not open, it looks kind of like a big round hole but its just a big round piece of aluminium where it mounts on the underside of the intake manifold.



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speaksgeek said:
This setup has been of great interest to me recently - I don't have it anymore, but it appears to be pretty important.
It's the PCV system. The large aluminium item is an oil/air separator.
Click to expand...

Yeah I wonder about just removing it. I had the whole manifold off at one point and was perplexed for a while by the complicated galleries. I was thinking of at least blocking off the canister and just having a single PCV pipe to the intake like on most cars. But Im also worried its important somehow haha.
I would leave the oil flow through the canister though rather than mess with that system incase it caused some kind of oil flow restriction or something. Would love to find some detailed diagrams of whats going on!

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speaksgeek said:
It is important. I advise don't change it, it'll be more annoyance than it's worth.
Click to expand...
Any info on how its important? Its been running fine with the valve wires disconnected for 3 months now. All the pipes are connected but the valve that was shorting is simply unplugged. Can only think it controls extra crank case ventilation sometimes. The main pipe is open all the time anyway so its not like the general crank case ventilation is blocked or anything

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